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CS Prop Installation

R

RVPilotDotCom

Member
Can anyone tell me what special tools ( crow foot wrench size... whatever ) I will need to install my CS Hartzell prop? This is my first and those bolts are very hard to get to, I can't even imagine what it will take to get them to the proper torque.

Thanks,

- Jim
 
Jim

The easiest route is a flat torque wrench such as the one shown below. They come in specific sizes and torques. Heres a good link for some choices...

http://www.aztecbolting.com/index.htm

http://www.aztecbolting.com/pdf/CDITorqueWrenchesPre-Set2005.pdf

-Jeff

1.JPG


or

6.JPG
 
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An open end wrench will suffice to tighten the nuts on the prop hub studs. I cut off a section of an open end wrench and welded it to a 1/2" drive socket. Then I calculated with the extra length to get the corrected torque value needed to torque the nuts. Or buy the special tool from Hartzell for $350.00. Other than the Hartzell double crows foot, I could not find one long enough that would work. About a 3" section from a quality open end wrench welded to an impact socket did the trick for me.

Roberta
 
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Try Avery

Avery Tools has a handy Hartzell wrench attachment for $39.00. It looks the same as the $200+ from the prop manufacturer and even comes with a torque conversion chart.
 
weld on a socket

to and old 3/4" open end wench...Or wrench even!...:)

Works geat, its free but remember it WON'T be a "certified" weld...Very important that....:)

Frank
RV7a...hopw my prop stays on?
 
Or the $2 solution. 3/4" combination wrench, bolt, washer, nut:

IMG_1364.jpg


IMG_1365.jpg


Nobody's mentioned it yet, but you should only finger tighten the prop bolts until the very end. If they are getting tight before the end, the prop isn't going on straight. You'll need to back off one or more and try again.
 
I did mine just like Larry....Oh, that's right, I stole the idea from his web site! (Thanks Larry...)

Paul
 
Great ideas!

Many thanks to all who responded.

I'm sure with all these great ideas, I should have no problems getting the job done.

Clear skies,

- Jim
 
Torque wrench angle

An A&P friend told me that putting the torque wrench 90 degrees from the extension means that the torque reading is accurate and you don't need to do any calculations. If the torque wrench is parallel to the extension then you need to do some math.

Anyone heard anything similar?
 
Nope not true. An extension is an extension no matter how you look at it. Typical torque wrenchs that use sockets attached measure the torque at that specific point (center of the socket). If you add to the length of that point you would need to subtract from the actual torque setting to get the desired torque needed at the bolt.
 
Not true

MCA said:
An A&P friend told me that putting the torque wrench 90 degrees from the extension means that the torque reading is accurate and you don't need to do any calculations. If the torque wrench is parallel to the extension then you need to do some math.

Anyone heard anything similar?
Click to expand...

Your still applying torque to the end of the open end wrench...Doesn't matter what angle you apply it...Dan Checkoway has a handy dandy torque extension calculator if you don't want to do the math.

Frank
 
You can borrow mine.

RVPilotDotCom said:
Can anyone tell me what special tools ( crow foot wrench size... whatever ) I will need to install my CS Hartzell prop? This is my first and those bolts are very hard to get to, I can't even imagine what it will take to get them to the proper torque.

Thanks,

- Jim
Click to expand...
Hi Jim, you can borrow mine if you need it. I machined it myself and it is heated treated and 1/2" thick, the calculations for torqueing are on the wrench. Let me know if you need to borrow it
dsc07517no5.jpg
.
 
MCA said:
An A&P friend told me that putting the torque wrench 90 degrees from the extension means that the torque reading is accurate and you don't need to do any calculations. If the torque wrench is parallel to the extension then you need to do some math.

Anyone heard anything similar?
Click to expand...
Your A&P friend is correct.

I don't want to sound rude, but there is some very dangerous advice being given in here. Advice that could lead to people improperly torquing their propellers.
frankh said:
Doesn't matter what angle you apply it
Click to expand...
Absolutely incorrect. The angle does matter. If you require proof, this link does the math to demonstrate.

PLEASE be more careful with this stuff! I hope Dan sees this and adds a caution to his calculator that the values given are only accurate if the extension is kept inline with the tool.
 
Joey's comments are absolutely correct. The angle matters, and this is not ambiguous to those who has studied physics and engineering, no offense intended to those who haven't. The link he refers to might not seem clear to those who haven't studied that sort of thing, but it is correct. While it is often fashionable to bash engineers with comments like "what do they know, I'm the one trying to get this thing to work", there are certain things that should be respected. Bolt torque settings are not simply to keep the bolt from loosening.

Please trust us on this one -

BTW, here is another good option for a torque wrench in the mid price range (about $200 with a crow's foot):

http://www.mcmaster.com/ and then go to page 2673. Item 5347A24 plus the appropriate size crow's foot on the same page works very nicely.
 
This is good info Joey. I appreciate you guys bringing this to our attention. Its nice to learn something everyday. I stand corrected. :rolleyes:

-Jeff
 
MCA said:
An A&P friend told me that putting the torque wrench 90 degrees from the extension means that the torque reading is accurate and you don't need to do any calculations. If the torque wrench is parallel to the extension then you need to do some math.

Anyone heard anything similar?
Click to expand...

Yup, its in the FAA circular.

Jekyll

Buy the Circular
Read the Circular
Be the Circular
 
Joey said:
Your A&P friend is correct.

I don't want to sound rude, but there is some very dangerous advice being given in here. Advice that could lead to people improperly torquing their propellers.
Absolutely incorrect. The angle does matter. If you require proof, this link does the math to demonstrate.

PLEASE be more careful with this stuff! I hope Dan sees this and adds a caution to his calculator that the values given are only accurate if the extension is kept inline with the tool.
Click to expand...

So lets say your torque wrench is set for 100ft lbs. Are you telling me that if I apply 100 ftlbs to the end of the extension with the wrench at zero degrees, it will be a different torque than if applied at 90 degrees?

I need to think about the math but intuitively the wrench is applying 100ftlb at the end of the extension no matter what the angle....

Probably a moot point ayway because I why would you use anything other than a straight wrench when torquing the prop bolts?

Either way,I believe the origional assertion was that if you applied the Twrench at 90 degrees to the extension then you could ignore the extension...This is definatly not true.

Frank
 
crows foot ect.

Thanks again for both the offer of the wrench extension ( found one in my tool box that would do - thx. ) and the additional info on places to find torque computations due to adding the additional length.

I think for the most part we are all in violent agreement here, but think about adding the crows foot to the end of a torque wrench as adding a cheater pipe on the end of a socket wrench. The longer the cheater the more torque you produce. It won't mater how many socket extensions you put on that socket wrench, until you bring out that cheater pipe that nut is not coming off.

So it is with the addition of the crows foot, it's like adding a mini cheater. It will cause a small increase in torque that has to be compensated for in your computations.


Clear skies,

- Jim
 
frankh said:
So lets say your torque wrench is set for 100ft lbs. Are you telling me that if I apply 100 ftlbs to the end of the extension with the wrench at zero degrees, it will be a different torque than if applied at 90 degrees?
Click to expand...
Yes. Anthing other than 90 degrees will change the mechanical advantage.
I need to think about the math but intuitively the wrench is applying 100ftlb at the end of the extension no matter what the angle....
Click to expand...
I can see how it would appear so, but once you do the math it becomes clear.
Probably a moot point ayway because I why would you use anything other than a straight wrench when torquing the prop bolts?
Click to expand...
I do it every day. Sometimes that's what it takes to get in there.
Either way,I believe the origional assertion was that if you applied the Twrench at 90 degrees to the extension then you could ignore the extension...This is definatly not true.

Frank
Click to expand...
It's 100% true.
 
RVPilotDotCom said:
So it is with the addition of the crows foot, it's like adding a mini cheater. It will cause a small increase in torque that has to be compensated for in your computations.
Click to expand...
Only if it adds the effective length of the tool. A crow's foot oriented 90 degrees to the wrench does not add to the effective length and adds no mechanical advantage.
 
Joey is correct, folks!

If anybody still doubts this issue, please follow the link Joey provided and do the math before posting. And thanks for the link, Joey. I'm going to save that PDF in my technical ref files.

William
Mechanical Engineer in a previous job lifetime.
Done the math on this issue quite a few times.
 
That is a handy tool. I'm glad to see this included:

torque.gif


Also, thanks to Dan C. for adding that caution notice to his online calculator.
 
frankh said:
So lets say your torque wrench is set for 100ft lbs. Are you telling me that if I apply 100 ftlbs to the end of the extension with the wrench at zero degrees, it will be a different torque than if applied at 90 degrees?

I need to think about the math but intuitively the wrench is applying 100ftlb at the end of the extension no matter what the angle....

Probably a moot point ayway because I why would you use anything other than a straight wrench when torquing the prop bolts?

Either way,I believe the origional assertion was that if you applied the Twrench at 90 degrees to the extension then you could ignore the extension...This is definatly not true.
Click to expand...
Sorry Frank, but you need to go back to physics class.

CASE 1 - extension in line with torque wrench

Let's assume you have your torque wrench set to 100 in-lb. Let's assume the distance between the hand grip and the square drive for the socket is 10 inches. If you put a socket on the wrench, and put it on a nut, you'll need to pull on the hand grip with a force of 10 lb to create a moment (torque) of 100 in-lb.

Now, let's imagine that you have an extension that is two inches long. You mount the extension so that it is aligned with the axis of the torque wrench, so the end of the extension is now 12 inches from the hand grip on the wrench. You put a socket on the extension, put it on a nut, and pull until the torque wrench clicks at 100 in-lb. How much torque have you put on the nut? The torque on the nut is the sum of two things:

1. The torque wrench applied a moment of 100 in-lb to the extension, and this moment is reacted at the nut.

2. You pulled on the torque wrench hand grip with a force of 10 lb, and this force is reacted where the torque wrench is attached to the extension. The 10 lb of force on the end of the extension creates a torque at the nut of 10 lb x 2 inches = 20 in-lb.

The total torque applied to the nut = the sum of 100 + 20 = 120 in-lb.

CASE 2 - extension at 90 deg to torque wrench

The 10 inch long torque wrench is still set to 100 in-lb. But now the 2 inch long extension is at 90 degrees to the torque wrench axis. We put a socket on the extension, put it on a nut, and pull until the torque wrench clicks at 100 in-lb. How much torque have you put on the nut? The torque on the nut is the sum of two things:

1. The torque wrench applied a moment of 100 in-lb to the extension, and this moment is reacted at the nut.

2. You pulled on the torque wrench hand grip with a force of 10 lb, and this force is reacted where the torque wrench is attached to the extension. This force is transferred through extension, and is reacted at the nut. How much torque does this force create at the nut? Well, the force is actually aligned with the axis of the extension. This is just like putting a wrench on a nut, and then pushing on the end of the wrench so that the direction of the push is directly towards the nut. You can push as hard as you want, and the nut won't turn, as the axis of the force is directly through the nut. The distance between the axis of this force and the centre of the nut is 0 inches, so the torque = 10 lb x 0 inches = 0 in-lb.

The total torque applied to the nut = the sum of 100 + 0 = 100 in-lb.
 
Don't do the math- just think!

Guys, this one's so easy it's silly! Hammer a nail about half way into some solid surface like a doorframe. If you are using a 3/8 drive torque wrench, hang the box end of a 3/8 inch combination wrench on the nail. Bring the open end of the wrench up to a level position, and slide it over the drive end of the torque wrench. Have the torque wrench set at its lowest setting. Now, with the torque wrench at a 90 degree angle to the combination wrench, steady the drive end of the torque wrench with one hand and apply force to the handle end of the torque wrench with your other hand. Make sure you are applying this force perpendicular to the handle. When the set torque is reached at the drive end, the wrench will "click". Have you applied any torque at all to the nail? Of course not! Visualize this with an even longer "adapter", and you'll get the idea.With a very short crowfoot adapter, at 90 degrees to the torque wrench, it probably wouldn't make enough difference- just know that the applied torque will be lower than what the wrench is set for.
 
Don't do the math- just think!

Guys, this one's so easy it's silly! Hammer a nail about half way into some solid surface like a doorframe. If you are using a 3/8 drive torque wrench, hang the box end of a 3/8 inch combination wrench on the nail. Bring the open end of the wrench up to a level position, and slide it over the drive end of the torque wrench. Have the torque wrench set at its lowest setting. Now, with the torque wrench at a 90 degree angle to the combination wrench, steady the drive end of the torque wrench with one hand and apply force to the handle end of the torque wrench with your other hand. Make sure you are applying this force perpendicularly to the handle. When the set torque value is reached at the drive end, the wrench will "click". Have you applied any torque at all to the nail? Of course not! Visualize this with an even longer "adapter", and you'll get the idea. With a very short crowfoot adapter, at 90 degrees to the torque wrench, it probably wouldn't make enough difference- just know that the applied torque will be lower than what the wrench is set for.
 
Yeah, yeah I get it now

Kevin Horton said:
Sorry Frank, but you need to go back to physics class.

CASE 1 - extension in line with torque wrench

Let's assume you have your torque wrench set to 100 in-lb. Let's assume the distance between the hand grip and the square drive for the socket is 10 inches. If you put a socket on the wrench, and put it on a nut, you'll need to pull on the hand grip with a force of 10 lb to create a moment (torque) of 100 in-lb.

Now, let's imagine that you have an extension that is two inches long. You mount the extension so that it is aligned with the axis of the torque wrench, so the end of the extension is now 12 inches from the hand grip on the wrench. You put a socket on the extension, put it on a nut, and pull until the torque wrench clicks at 100 in-lb. How much torque have you put on the nut? The torque on the nut is the sum of two things:

1. The torque wrench applied a moment of 100 in-lb to the extension, and this moment is reacted at the nut.

2. You pulled on the torque wrench hand grip with a force of 10 lb, and this force is reacted where the torque wrench is attached to the extension. The 10 lb of force on the end of the extension creates a torque at the nut of 10 lb x 2 inches = 20 in-lb.

The total torque applied to the nut = the sum of 100 + 20 = 120 in-lb.

CASE 2 - extension at 90 deg to torque wrench

The 10 inch long torque wrench is still set to 100 in-lb. But now the 2 inch long extension is at 90 degrees to the torque wrench axis. We put a socket on the extension, put it on a nut, and pull until the torque wrench clicks at 100 in-lb. How much torque have you put on the nut? The torque on the nut is the sum of two things:

1. The torque wrench applied a moment of 100 in-lb to the extension, and this moment is reacted at the nut.

2. You pulled on the torque wrench hand grip with a force of 10 lb, and this force is reacted where the torque wrench is attached to the extension. This force is transferred through extension, and is reacted at the nut. How much torque does this force create at the nut? Well, the force is actually aligned with the axis of the extension. This is just like putting a wrench on a nut, and then pushing on the end of the wrench so that the direction of the push is directly towards the nut. You can push as hard as you want, and the nut won't turn, as the axis of the force is directly through the nut. The distance between the axis of this force and the centre of the nut is 0 inches, so the torque = 10 lb x 0 inches = 0 in-lb.

The total torque applied to the nut = the sum of 100 + 0 = 100 in-lb.
Click to expand...

Actually I took about 10 mins sketching this out and decided indeed its not just the torque but also the force applied and the reaction therof.

The reason the extension can be ignored of course is that the effective is not the hypotenuse of the angle becuse the force is at 90 degrees to the torque wrench

It was not obvious though....Yup too long out of school

In short keep yer torque wrench aligned with the extension an use Dan's calculator...

Frank
 
Another converter

Hi.

I'm about to torque the prop bolts and found this handy converter: (when you need to put on a crow foot for example)

http://www.belknaptools.com/extcalc.asp

It works when the extension is less than zero too, just measure the actual length it adds to the length of the wrench (look at the pic and you'll know what I mean)

On the left side is a handy torque converter which looks like a calculator.
Nice for us metric guys who sometimes needs to convert into inches and pounds....
 
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Don't forget the Vaseline.......

From my past Air Force hydraulic/pneumatic shop experiences......you should smear a bit of Vaseline on the internal "O" ring inside the prop hub, just enough to make it slippery. Also rub just a bit of Vaseline on the end of the crankshaft where the "O" ring will slide onto. This will allow the the "O" ring to slide over the crankshaft end without causing any damage to that "O" ring. Chances are that the "O" ring wouldn't roll out, be pinched or cut, but the Vaseline would positively avert that situation. Better to be safe than sorry.
 
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